System and method for construction of log structure

ABSTRACT

A system and method for constructing a log structure includes logs having pairs of parallel spaced apart longitudinally extending grooves on opposing sides of the logs. Inner edges of the grooves may be tapered inwardly to receive lumber support pieces. A wall is constructed by providing a base log having a pair of parallel spaced-apart longitudinally extending grooves on an upper surface of the log, inserting lower edges of a pair of lumber support pieces into the grooves, and positioning the grooves of a log over upper edges of the lumber support pieces. Further lumber support pieces and logs are attached in like manner until the desired height is reached. A corner piece for forming corners of the structure having vertically extending channels for receiving ends of the lumber support pieces is provided.

TECHNICAL FIELD

This invention relates to the manufacture and construction of wooden log structures, and in particular to the manufacture and construction of wooden log structures using logs of non-uniform shape.

BACKGROUND

Conventional construction of a log structure involves scribing the bottom of each log being placed successively above the log below to form a rising wall in such a way that it fits closely with the log that it is to be placed above. Scribing is done using various guidelines, and usually involves cutting the desired shape with a manually operated chainsaw. A disadvantage of this method is that it requires “House Logs”, which are expensive to acquire because they must be very straight with limited taper, so that they may be fitted together with a minimal amount of reshaping from the log home builder operating the chainsaw. Such persons have generally trained as a log builder under the guidance of a more experienced teacher with years of experience. Consequently, they are very highly paid workers. This “Scribe Method” for building log structures is still very slow, with only a few logs being prepared each day. This inevitably results in an expensive log structure.

Another method which is more automated involves milling sawn timbers, so the resulting pieces fit tightly together in a vertical stacked relationship. The sawn timbers are shaped to look like small logs. This method is still quite expensive, and results in difficulties in supplying electricity to the dwelling, or hiding plumbing from view. Further, the insulating capacity of the relatively thin wooden walls is relatively low.

There is thus a need for a design of a log structure that is suitable for use with logs of uneven shape, and which permits the concealment of electrical or plumbing infrastructure while providing good insulative capabilities.

The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

SUMMARY

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.

A system for building a log structure is provided. A plurality of logs are provided. Each log has one pair of parallel spaced apart longitudinally extending grooves on one surface, and one pair of parallel spaced-apart longitudinally extending grooves on a second surface of the log opposite the first surface. A plurality of lumber support pieces are provided, first edges of the lumber support pieces being dimensioned to engage the grooves on the first surface of the logs, and second edges of the lumber support pieces being dimensioned to engage the grooves on the second surface of the logs. Inner edges of each groove may be tapered inwardly from the outer surface of the log towards the base of the groove. The grooves may be milled to a uniform shape, regardless of the exterior dimensions of the log. The system may include corner posts having two pairs of longitudinally extending parallel channels dimensioned to receive ends of the lumber support pieces. The system may also include an insert dimensioned to be inserted between the ends of the logs and the channels of the corner posts.

A method for building a log wall is provided. A base log having two parallel spaced apart grooves on an upper edge of the base log is provided, as are a plurality of lumber support pieces dimensioned to fit into the grooves. Each lumber support piece has upper and lower edges and ends. A plurality of logs are provided. Each log has a pair of parallel spaced-apart longitudinally extending grooves on both an upper and a lower surface of the log. A base log is positioned at the desired location of the log wall, and a lower edge of each one of a first pair lumber support pieces is inserted into one of the grooves on the upper edge of the base log. The grooves on a lower surface of a first log are inserted onto upper edges of the first pair of lumber support pieces. Lower edges of each one of a second pair of lumber support pieces are inserted into each of the grooves on the upper edge of the first log. Successive layers of logs and lumber support pieces may be added in like manner until the desired height of the log wall is achieved. The inner edges of the grooves may be provided with an inward taper from the outside of the log toward the base of the groove. The grooves may be milled to a uniform shape, regardless of the exterior dimensions of the logs.

A log structure is provided. The log structure has at least one base log with two parallel spaced apart grooves on an upper surface of the base log. Lower edges of each one of a first pair of lumber support pieces are fittingly engaged with one of the grooves on the base log. The log structure has at least one log with a pair of parallel spaced apart longitudinally extending grooves on an upper surface and on a lower surface of the log, the grooves on the lower surface of the log being fittingly engaged with upper edges of the first pair of lumber support pieces. The log structure has at least a second pair of lumber support pieces, lower edges of each one of the second pair of lumber support pieces being fittingly engaged with one of the grooves on the upper surface of the at least one log. The structure may have further layers of logs and lumber support pieces joined in like manner to provide a log wall of the desired height above each of the at least one base logs.

The structure may have at least one corner post with two pairs of longitudinally extending parallel channels dimensioned to receive ends of the lumber support pieces. First ends of all of the lumber support pieces above a first end of the at least one base log are engaged with the channels of the corner post. The structure may further include at least one insert between the ends of the logs and the channels of the at least one corner post. Spaces defined between adjacent logs and a pair of lumber support pieces may be used to run electrical wiring or plumbing, or may be filled with insulation. An inner edge of each groove may taper inwardly from the outer surface of the log towards the base of the groove. The grooves may be milled to a uniform shape, regardless of the exterior dimensions of the log.

A log wall including a plurality of logs, each log having at least one groove on an upper surface of the log and at least one groove on a lower surface of the log, and also including a plurality of lumber support pieces having edges dimensioned to engage with the grooves on the logs, is also provided. The wall is formed by alternating vertical layers of lumber support pieces and logs, such that the edges of the lumber support pieces are engaged with the grooves of the logs. A second wall portion spaced apart from and extending parallel to a first wall portion and constructed in like manner may be provided.

In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF DRAWINGS

Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

FIG. 1A is an end view of an embodiment of a portion of a log wall 10 made in accordance with one aspect of the invention.

FIG. 1B is a perspective view of the FIG. 1A embodiment.

FIG. 2 is an end view of an embodiment of a log 20 showing grooves 24, 26 with inwardly tapered inner edges.

FIG. 3 is a schematic drawing showing how grooves 24, 26 may be made in a curved log 21.

FIGS. 4A-4C show different embodiments of a base log. FIG. 4A is an end view of a base log 36A that is the same as logs 20. FIG. 4B is an end view of a base log 36B wherein the lower surface of the log is cut to provide a flat edge 38. FIG. 4C is an end view of a base log 36C wherein the lower surface of the log has been cut to provide a flat edge 38′, which includes lower grooves 26′ to receive lumber support pieces 22.

FIG. 5 is a perspective view of an embodiment of a log wall 10 wherein electrical wiring is provided within space 40.

FIG. 6 is an end view of an embodiment of a portion of a log wall 12 made in accordance with another aspect of the invention.

FIG. 7 is an end view of an embodiment of a log wall 16.

FIGS. 8A-8D show the construction of a corner 56 of a log structure 14. FIG. 8A shows the engagement of logs 20 with corner post 58. FIG. 8B shows a possible placement of optional guide bolts 62 on logs 20. FIG. 8C shows a corner portion 56 wherein ends 64 of lumber support pieces and channels 60 of the corner post 58 have been half-dovetailed. FIG. 8D shows an embodiment of a corner 56 wherein the angle between the walls of the log structure is 135°.

FIG. 9 shows an embodiment of a roofing structure made from logs 20 and roofing panels 66.

FIG. 10 is an exploded view of an alternative embodiment of a corner 56 that includes an insert between the ends of logs 20 and channels 60.

DESCRIPTION

Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

With reference to FIG. 1A, a log wall 10 may be formed from a series of logs 20 and lumber support pieces 22. As best illustrated in FIG. 2, a log 20 for use in the construction of wall 10 is provided with two pairs of parallel grooves 24, 26 on opposing sides of the log, preferably by milling the log. Grooves 24, 26 preferably extend longitudinally throughout the length of log 20, and are milled to a uniform shape, regardless of the local diameter of log 20, to receive lumber support pieces 22 of uniform dimensions. The resulting distance between the top edge 25 and bottom edge 27 of lumber support pieces 22 is log gain 23. While log gain 23 may be the same for all logs used, in order to maintain layers of logs 20 with a uniform spacing, it is not necessary that log gain 23 be the same. Use of a varying log gain 23 may be efficient, for example, where logs 20 of widely differing diameters are to be used, to avoid wood waste by cutting excessively deep channels 24, 26 in logs 20 of larger diameter. Accordingly, regardless of the diameter of the logs used, or the variations in shape or taper of logs 20, log wall 10 may be rapidly and readily constructed from such logs, because logs 20 may be prepared off-site and in large quantities.

An example of how grooves 24, 26 on a curved log 21 allow curved log 21 to be used in the construction of log wall 10 is shown in FIG. 3. Because grooves 24 and 26 are milled to be of a uniform, preferably straight shape, regardless of variations in the shape or taper of log 20 or curved log 21, grooves 24, 26 will be of proper size and orientation to receive lumber support pieces 22. Accordingly, logs 20 or 21 may be prepared off-site and before construction of log wall 10, without the need for a skilled craftsperson, thereby greatly reducing the time and cost previously associated with the construction of a log structure.

Each of grooves 24, 26 has inner edges, shown respectively as 24A and 26A, and outer edges, shown respectively as 24B and 26B. Outer edges 24B and 26B are vertical or nearly vertical when log 20 is in the installed orientation. Inner edges 24A and 26A may be tapered slightly inwardly from the outside edge of log 20 toward the base of grooves 24, 26. Thus, the opening of grooves 24, 26 may be wider than the base of grooves 24, 26. In some embodiments, the angle θ between the base of the groove 24 or 26 and the inner edge 24A or 26A is 93°. The tapered inner edges of grooves 24, 26 force lumber support pieces 22 towards the outer edges 24B, 26B of grooves 24, 26. This design permits lumber support pieces 22 to be more easily inserted into grooves 24, 26, and also results in log wall 10 becoming tighter as the weight of logs 20 presses down on lumber support pieces 22. This design also has the advantage of permitting less water to leak into the joint on the outside surface of log wall 20 than would be the case if inner edges 24A and 24B were not tapered.

To form a log wall 10, a base log is provided. The base log may be formed in the same manner as logs 20, as illustrated, for example, by base log 36A in FIG. 4A. Lumber support pieces 22 may then be placed on the ground, foundation, or other structure that is intended to support log wall 10, and lower grooves 26 of base log 36A may receive lumber support pieces 22. Alternatively, the base log may be cut to provide a flat edge 38. Flat edge 38 may itself contact the ground, foundation, or other structure that is intended to support log wall 10, as illustrated by base log 36B in FIG. 4B. In that case, it will be appreciated that log 36B may be provided without lower grooves 26. Alternatively, flat edge 38′ may include lower grooves 26′ to receive lumber support pieces 22, as illustrated for example by base log 36C in FIG. 4C. In the embodiment of FIG. 4C, lumber support pieces 22 extending from lower grooves 26′ would contact the ground, foundation, or other structure intended to support log wall 10. Preferably, the base log of wall 10 is placed on a concrete slab or concrete perimeter foundation, to ensure that water does not collect around the base log. Logs 20 may also be treated with suitable preservatives to ensure that logs 20 do not decay over time.

Log wall 10 may then be built upon base log 36A, 36B or 36C by successively inserting lumber support pieces 22 into upper grooves 24 of the base log, then positioning lower grooves 26 of a log 20 over the upper edges of lumber support pieces 22. The weight of log 20, and of log wall 10 as the wall is constructed, will cause lumber support pieces 22 to be tightly inserted into grooves 24 and 26, thereby providing strength to log wall 10. Log wall 10 may be built to the desired height by likewise continuing to provide alternate layers of logs 20 and lumber support pieces 22.

A log wall 10 constructed as described above, i.e. wherein logs 20 have pairs of parallel grooves, provides an open space 40 (see FIGS. 1A and 5) defined between two adjacent logs 20 and the two parallel lumber support pieces 22 positioned therebetween. Open space 40 may be used to provide a space to run electrical wiring throughout a log building structure, as shown in FIG. 5, or for plumbing in warmer climates. If it is desired to run electrical wiring in open space 40, sealed wire runs 42 would be supported in place as log wall 10 is being constructed, as shown in FIG. 5. Sealed wire runs 42 could be hung out of pre-cut electrical box openings, so that sealed wire runs 42 could be tied together and locked up after log wall 10 has been erected. In this manner, electrical wiring may be directed to switch boxes or electrical outlets 44 where desired within the structure.

Open spaces 40 may also be insulated to a higher R factor than the wooden log itself by providing pre-cut holes (not shown) in those lumber support pieces 22 which will be on the interior of the structure. An expanding foam insulation, which may be for example Icynene™, may be blown into spaces 40, and the pre-cut holes thereafter plugged to provide a smooth interior wall surface.

In an alternative wall structure 12 shown in FIG. 6, each log 48 is provided with one single groove 50 on each of its opposing surfaces. Grooves 50 are dimensioned to fittingly engage edges 25, 27 of lumber support pieces 22. A log wall structure 12 may be constructed by forming a first wall portion 52 comprising alternating layers of logs 48 and lumber support pieces 22. An adjacent second wall portion 54 extending parallel to first wall portion 52 and spaced a desired distance apart therefrom may likewise be formed from alternating layers of logs 48 and lumber support pieces 22 to form wall structure 12. Preferably the vertical elevation of logs 48 in the first and second wall portions 52, 54 is staggered, to permit first and second wall portions 52, 54 to be positioned in close lateral proximity. Additionally, smaller logs may be used to construct alternative wall structure 12 than would ordinarily be used to construct log wall 10, because only a single groove 50 must be cut into log 48. With this construction, an open space 55 is defined between first and second wall portions 52, 54. Open space 55 may be used to run electrical wiring or plumbing pipe, or be filled with expanding foam insulation, as described above with reference to space 40.

If it is not necessary or desired to define an open space 55 between the wall portions of wall structure 12, then a single wall portion 52 or 54 may be constructed as described above, to serve as log wall 16, shown in FIG. 7. In the construction of log wall 16, logs of larger diameter and lumber support pieces 22 of greater width may be used to provide a more substantial wall 16.

With reference to FIG. 8A-8D, to construct a corner 56 of a log structure 14, a timber log corner post 58 may be used. Timber log corner post 58 may be, for example, one quarter of a rounded log. Timber log corner post 58 includes a pair of longitudinally extending spaced apart channels 60, which are vertically oriented when corner post 58 is in the installed configuration. The space between channels 60 corresponds to the space between grooves 24, and between grooves 26, on logs 20, so that lumber support pieces 22 project into channels 60 when structure 14 is assembled (see FIG. 8A). Steel guide bolts 62 may be affixed to logs 20 at each end of log 20, and secured in timber log corner post 58 in channels 60, for example as shown in FIG. 8A and FIG. 8B.

With reference to FIG. 8C, the ends 64 of lumber support pieces 22 may also or alternatively be half-dovetailed to allow for shrinkage and movement of structure 14, while preventing lumber support pieces 22 from being pulled out from vertical channels 60. In embodiments where the ends 64 of lumber support pieces 22 are half-dovetailed, channels 60 will be half-dovetailed in corresponding fashion to engage with the ends of lumber support pieces 22. However, the ends 64 may be profiled with a slightly smaller half-dovetail than channels 60, to allow for movement or shrinkage of structure 14, while still preventing ends 64 from being pulled out from vertical channels 60.

While in the illustrated embodiments a corner post 58 providing an approximately 90° angle has been shown to describe the construction of corner 56, it will be appreciated that corner 58 could be constructed to define other angles, depending on the desired shape of log structure 14. For example, as illustrated in FIG. 8D, corner post 58 could be configured to provide an angle of 135° between intersecting log walls if it was desired to construct a log structure 14 having an octagonal shape.

With reference to FIG. 10, an insert such as floating wooden key stock 70 may be inserted between the ends of logs 20 and corner post 58 in channels 60. Floating wooden key stock 70 is preferably cut from framing lumber, and is preferably cut across the grain to allow for shrinkage. Floating wooden key stock 70 is cut to appropriate dimensions to match the log gain 23 of log 20 and the depth of channel 60, so as to fill the space defined between the end of log 20 and channel 60. Optionally, end grain channels 72 may be cut into logs 20, to receive wooden key stock 70. In this case, floating wooden key stock 70 is cut to an appropriate dimension to fill the space defined by channel 60 and end grain channels 72. Use of floating wooden key stock 70 prevents air from flowing freely through the spaces defined between the end of log 20 and channel 60.

To construct a log structure 14, an appropriate number of base logs may be positioned at the desired location of log walls 10 of the structure. Corner posts 58 providing the desired angle of intersection of log walls 10 may then be positioned at the corners 56 of structure 14, so that channels 60 in corner posts 58 are aligned with grooves 24 of base log 36. Corner posts 58 may optionally be coupled to base logs 36, for example with steel guide bolts 62 as described earlier. During construction of structure 14, corner posts 58 are preferably supported in a vertical orientation, to ensure that log walls 10 do not tilt or lean. For example, bridging pieces of lumber (not shown) may be used to secure corner posts 58 in a vertical orientation during construction of structure 14.

Lower edges of a first layer of lumber support pieces 22 may then be slid vertically down channels 60 and inserted into grooves 24. Provided that lumber support pieces 22 are longer than log 20, their ends can extend into channels 60. Of course, the ends 64 of lumber support pieces 22 should not extend past the ends of logs 20 by a length longer than the depth of channels 60. A first layer of logs 20 may then be built up by fitting grooves 26 of a log over upper edges 25 of the lumber support pieces. Successive layers of logs 20 and lumber support pieces 22 may be built up in like manner, to form walls 10 of log structure 14.

As can be seen from FIG. 9, logs 20 or 48 and lumber support pieces 22 may also be joined in similar fashion to construct a roofing structure. Logs 20 or 48 may be coupled to joists or beams of a roof. Roofing panels 66 may be inserted into grooves 24, 26 or 50 in logs 20 or 48 respectively. Roofing panels 66 have a similar shape to lumber support pieces 22; however, roofing panels 66 are inserted transversely rather than longitudinally into grooves 24, 26 or 50 (in other words, their ends rather than their sides are inserted into the grooves), and may be of shorter length than lumber support pieces 22, so as to provide a short span of roof between logs 20 or 48. If logs 20 are used in the construction of a roofing structure, the resulting space 68 defined between opposing pairs of roofing panels 66 extending between logs 20 may be filled with expanding foam insulation as described with reference to space 40, thereby increasing the R value of the roof.

Although the embodiments described above have been described with reference to building materials constructed from wood, it will be appreciated that the construction techniques described above could likewise be applied to logs 20 and support pieces 22 made from any materials suitable for constructing a structure, including metal, plastic or rubber.

Additionally, while the lumber support pieces 22 and grooves 24, 26 have been described as extending longitudinally along the length of logs 20, it will be appreciated that shorter lumber support pieces could be placed longitudinally in end-to-end relationship, continuously or discontinuously, to achieve substantially the same function. Further, while for ease of construction, lumber support pieces 22 will generally be of uniform dimensions (i.e. the width of top edge 25 will generally be the same as the width of bottom edge 27), it will be appreciated that the dimensions of edges 25, 27 could differ, provided that the dimensions of grooves 24, 26 are adjusted accordingly, without departing from the scope of the invention.

It will also be appreciated that in some embodiments, additional support may be provided to log walls 10 by, for example, providing holes that extend vertically through wall 10 and inserting structural steel through the holes. Optionally, the ends of the structural steel may be threaded, and a bolt affixed to each end, so that the bolts may be tightened over time as logs 20 shrink.

While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope. 

1. A system for building a log structure comprising: a plurality of logs, each log comprising one pair of parallel spaced-apart longitudinally extending grooves on a first surface of the log and one pair of parallel spaced-apart longitudinally extending grooves on a second surface of the log opposite to the first surface; and a plurality of lumber support pieces; wherein first edges of each of the lumber support pieces are dimensioned to engage the grooves on the first surface of one of the plurality of logs, and second edges of each of the lumber support pieces are dimensioned to engage the grooves on the second surface of another one of the plurality of logs.
 2. A system according to claim 1 further comprising a base log having a pair of spaced-apart longitudinally extending grooves on an upper surface of the base log.
 3. A system according to claim 2 wherein the base log comprises a flat edge on the lower surface of the base log.
 4. A system according to claim 1 wherein an inner edge of each groove tapers inwardly from the outer surface of the log towards the base of the groove.
 5. A system according to claim 4 wherein an angle defined between the inner edge of each groove and the base of the groove is 93°.
 6. A system according to claim 1 wherein the grooves are milled to a uniform shape, regardless of the exterior dimensions of the log.
 7. A system according to claim 1 further comprising one or more corner posts, each corner post comprising two pairs of longitudinally extending parallel channels dimensioned to receive ends of the lumber support pieces.
 8. A system according to claim 7 wherein an angle defined between the lumber support pieces when inserted into the corner posts is 90°.
 9. A system according to claim 7 further comprising an insert dimensioned to be inserted between the ends of the logs and the channels of the corner posts.
 10. A system according to claim 7 wherein the channels of the corner posts are half-dovetailed, and the ends of the lumber support pieces are correspondingly half-dovetailed with a smaller size than the corner posts.
 11. A system according to claim 1 wherein at least one of the logs is of non-uniform shape or taper.
 12. A method for building a log wall comprising: providing a base log having two parallel spaced apart grooves on an upper edge of the base log; providing a plurality of lumber support pieces dimensioned to fit into the grooves, each lumber support piece having upper and lower edges and ends; providing a plurality of logs, each log comprising a pair of parallel spaced-apart longitudinally extending grooves on both an upper and a lower surface of the log; positioning the base log at the desired location of the log wall; inserting a lower edge of each one of a first pair of the lumber support pieces into a corresponding one of the grooves on the upper edge of the base log; inserting grooves on the lower surface of a first one of the logs onto upper edges of the first pair of lumber support pieces; inserting lower edges of each one of a second pair of the lumber support pieces into a corresponding one of the grooves on the upper edge of the first one of the logs; and adding successive layers of logs and lumber support pieces in like manner until the desired height of the log wall is achieved.
 13. A method according to claim 12 further comprising providing an inner edge of the grooves with an inward taper from the outside of the log toward the base of the groove.
 14. A method according to claim 12 further comprising milling the grooves to a uniform shape, regardless of the exterior dimensions of the logs.
 15. A log structure comprising: at least one base log having two parallel spaced apart grooves on an upper surface of the base log; a first pair of lumber support pieces, lower edges of each one of the first pair of lumber support pieces being fittingly engaged with a corresponding one of the grooves on the at least one base log; at least one log having a pair of parallel spaced apart longitudinally extending grooves on an upper surface and on a lower surface of the log, the grooves on the lower surface of the log being fittingly engaged with upper edges of the first pair of lumber support pieces; at least a second pair of lumber support pieces, lower edges of each one of the second pair of lumber support pieces being fittingly engaged with a corresponding one of the grooves on the upper surface of the at least one log; and further layers of logs and lumber support pieces joined in like manner to provide a log wall of the desired height above each of the at least one base logs.
 16. A structure according to claim 15 further comprising at least one corner post, the at least one corner post comprising two pairs of longitudinally extending parallel channels dimensioned to receive ends of the lumber support pieces, wherein first ends of all of the lumber support pieces above a first end of the at least one base log are engaged with the channels of the corner post.
 17. A structure according to claim 16 further comprising at least one insert between the ends of the logs and the channels of the at least one corner post.
 18. A structure according to claim 15 wherein an inner edge of each groove tapers inwardly from the outer surface of the log towards the base of the groove.
 19. A structure according to claim 15 wherein the grooves are milled to a uniform shape, regardless of the exterior dimensions of the log.
 20. A structure according to claim 15 wherein spaces defined between adjacent logs and a pair of lumber support pieces therebetween is used to run electrical wiring, to run plumbing, or to contain insulation.
 21. A log wall comprising: a plurality of logs, each log having at least one groove on an upper surface of the log and at least one groove on a lower surface of the log; and a plurality of lumber support pieces, the edges of the lumber support pieces being dimensioned to engage with the grooves on the logs; wherein the wall is formed by alternating vertical layers of lumber support pieces and logs, the edges of the lumber support pieces being engaged with the grooves of the logs.
 22. A log wall according to claim 21 wherein a first wall portion is formed by alternating vertical layers of lumber support pieces and logs, and wherein a second wall portion spaced apart from and extending parallel to the first wall portion is formed in like manner by alternating vertical layers of lumber support pieces and logs. 